Generally, laser light mainly has intensity distribution which is most strong near a center of a light axis and gradually weaker toward a periphery of the light axis, described as Gaussian distribution. However, with laser machining (laser processing), laser light with even intensity distribution in space has been required. With respect to the laser light with even intensity distribution, non-patent literature 1 discloses a kaleidoscope type homogenizer as an optical component for shaping laser light which shapes intensity distribution of laser light into spatially even intensity distribution, and patent literature 1, 2 and 3 disclose an aspheric lens type homogenizer as an optical component for shaping laser light which shapes intensity distribution of laser light into spatially even intensity distribution.
The aspheric lens type homogenizer disclosed in the patent literature 1 includes a pair of aspheric lenses which have a shape deduced by a geometrical optics method, and converts intensity distribution of incident laser light with an intensity profile of Gaussian distribution into top-hat shaped intensity distribution. On the one hand, the aspheric lens type homogenizer disclosed in the patent literature 2 includes a pair of aspheric lenses which have a shape deduced by an undulate optics (a wave optics) method, and converts intensity distribution of incident laser light with an intensity profile of Gaussian distribution into top-hat shaped intensity distribution. On the other hand, the aspheric lens type homogenizer disclosed in the patent literature 3 includes a pair of aspheric lenses, and converts intensity distribution of incident laser light with an intensity profile of Gaussian distribution into intensity distribution corresponding to super Gaussian distribution.